Speed Demons

By Barry Pangrle
For extreme world record performance levels, the required power levels are also typically extreme. It’s that age-old battle against diminishing returns to squeeze out every last drop of performance versus practical limits and wallets.

For example, a top fuel dragster can consume about six gallons of fuel for a quarter-mile run down the strip. As has previously been shown here, x86 clock frequencies have gone from doubling nearly every year to practically stagnant over the past seven. Of course, power has been a major player in putting a ceiling on those frequencies. So in honor of that high-speed clock demon that was released back in November 2004, the Intel Pentium 4 HT 570J, we will look at recent new records in x86 (over) clocking frequencies (“overclocking” is a term used for pushing a chip past its specified clock frequency).

AMD recently released its new “Bulldozer” based x86 parts that are composed of modules with two separate integer paths that share floating-point resources. Roughly speaking, the concept is to get two “cores” into one module that uses slightly more area than a standard single core. Breaking from the current trend of not designing for higher clock speeds, Bulldozer in fact seems to have been architected to run at somewhat higher clock frequencies. This new part presented itself as an opportunity for the over-clocking community to jump in and try to break the previous record held by an Intel Celeron D 352 clocked at 8308.94 MHz.

Heat kills chips, and if the clock is pushed past a part’s rated frequency, dynamic power typically increases linearly with the clock frequency so that the heat produced from the chip also will increase. One trick used by overclockers is to also increase the supply voltage to help increase the chip’s ability to run at a higher clock frequency. As you might imagine, because the dynamic power increases quadratically with the voltage, this can really increase the amount of heat being generated. Overclockers typically use more exotic cooling than the standard heatsink fan often provided with a boxed part. The cooling solutions range from larger heatsinks made of metals that have good thermal conductivity, like copper, to elaborate liquid cooling systems that on the far end of the spectrum included liquid nitrogen and liquid helium.

As part of the launching of these new parts, AMD held an extreme overclocking session to go after the record. There’s an entertaining video here on YouTube (it’s just a bit over two minutes long and looks pretty good at 1080p). The result was what looked like a fairly stable 8.429 GHz—assuming you kept the liquid helium flowing. The power for the part wasn’t reported, but that top fuel dragster comes to mind.

Since then an overclocker in Taiwan named Andre Yang has twice reported faster results, and I’ve included them in the table below along with an image of the setup shown in the AMD video. It’s interesting to note that the first three entries are all running within 16 mV of 2.0 V. Even the P4 570J ran at only 1.425 V and that was in a 90 nm technology. It looks like Andre was able to crack 8.5 GHz by pushing the voltage to 2.064 V. It could possibly be that the max voltage before part failure ultimately will limit how high these clock frequencies could go.

Not to be left out, the memory community has also gotten into the game of setting new records recently and you can find more here about Corsair’s DDR3-3467 memory. Coincidentally or not, it was also run with an FX-8150 liquid nitrogen-cooled PC.

So, you might be wondering, if it’s possible to take these parts and bump up the voltage to run them faster, if you were to run them slower would it be possible to reduce the voltage levels to further reduce power? The answer is of course “yes,” and we might just look at that in a future blog too.

Best Wishes for a Happy, Healthy and Prosperous 2012!